They might be ok while the Oscar is small, but when it reaches 6 inches in length, it will eat them. And eventually the Oscar will reach a foot in length so you need a big tank with big tank mates for an Oscar.
I figure I’m going to have a hard time getting these danios out of the tank with them being so quick. So I’ll just let natural selection do it’s deal if it eventually comes to it. Hopefully it won’t though.